<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>判断数据类型的几种方法</title>
</head>
<body>
<script>
    console.log(typeof 'abc') // string
    console.log(Object.prototype.toString.call('abc')) // [object String]
    console.log('abc'.constructor == String) // true
</script>
</body>
</html>
